Burner for liquid fuels



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Filed June l, 1944 W HUBER BURNER FOR LIQUID FUELS April 17, `1951 Patented pr. i7, 1951 2,549,092 A BURNER Fon LIQUID FUELS Walter Huber, Winterthur, Switzerland, assignor to Sulzer Freres, Societe Anonyme, Winterthur,

Switzerland Application June 1, 1944, Serial No. 538,279 In Switzerland October 19, 1943 8 Claims.

The invention relates to a burner for liquid fuels having immediately before the combustion chamber a nozzle chamber in which the fuel performs a rotary movement and to which a return pipe for fuel is connected. f N It is known in burners for liquid fuelsto supply more fuel to the nozzle chamber than is injected into the combustion chamber and to return the surplus fuel through a return pipe. The fuel then rotates in the nozzle chamber and leaves this chamber through openings situated in the axis of the burner. This has the disadvantage that the injection of the fuel into the combustion chamber is impaired, in that irregularities may arise in the interior of the rotating fuel ring on account of the fuel Aflowing out of the nozzle chamber in the burner axis, and theseirregularities may cause a disturbance in the fuel emerging and thus an irregular and even slanting flame formation.

This disadvantage is overcome by the invention in that the nozzle chamber is provided in the region of its outer circumference with a return fiow opening which connects it to the return pipe.

The drawings show embodiments of the invention in a diagrammatic form. y

Fig. 1 is a longitudinal section through the burner,

Fig. 2 is a view of the fuel supply passages,

Figs. 3 to 5 show further designs of the nozzle chamber.

The fuel enters the burner I through the passage 2 and flows through the centrally placed burner pipe 3 and theopenings 4 of the swirl body 5 with the spiral grooves 6 (Fig. 2), in

which the pressure is converted into velocity. The spiral grooves 6 open tangentially into the nozzle chamber l, which is formed by the end face of the swirl body 5, the intermediate piece 8 and the nozzle cap 9.

On the outer circumference of the nozzle chamber 1, between the intermediate piece 8 and the nozzle cap 9, is provided the slot-shaped outlet I0, which connects the nozzle chamber 'I to the return pipe II, I2, I3. Built into the return pipe is the throttle member I4, which regulates the ow through the pipe I3. The cooler I5 for cooling the returning fuel prevents the formation of froth and thus any impairment of throttling in the regulating member I4.

The nozzle opening IE in the burner cap 9 is closed by the spring I8 acting on the needle I'I when the fuel pressure falls below a certain value. The burner pipe 3 is screwed into the intermediate piece 8 and serves to hold fast the swirl body 5. By means of the spring I9 and also through the pressure of the fuel on the end 29 of the pipe 3 the intermediate piece 8 is pressed rmly against the cap 9, which is supported on the jacket pipe 2| of the burner I. The end 20 of the nozzle pipe 3 is fitted into the outer end of the burner I so as to have a sealing effect, but is also displaceable in order to prevent any change in the slot I0 in case of expansion of the various parts of the burner.

The regulating valve I4 is adjusted by means of a setting device 22 which is in itself known and which Works in dependence on a determinant service magnitude of the plant according to the purpose for which the burner I is used and regulates the quantity of fuel returning. Obviously the valve I4 may also be adjusted by hand, either exclusively or in combination with the device 22.

The regulation of the quantity of fuel returning permits a pressure sufficient for the faultless atomisation of the fuel injected to be maintained before the grooves 6 even when the load is 10W. This regulation even renders it possible to prevent the atomisation of fuel by opening the valve I4 completely, and thus to turn off the burner in such a Way that on the one hand no dripping takes place and on the other, by a sudden closing of the valve I4, the immediate atomisation of the complete fuel quantity becomes possible.

Regulation can take place in such a way that the quantity of fuel entering the burner I is kept constant for all loads. The returning quantity of fuel, however, can also be kept constant, in which case this quantity must be so great that the pressure before the grooves 6 remains high enough at all conditions of loading to ensure good atomisation of the fuel quantity emerging through the opening I6.

The needle I'I is opened at a certain fuel pressure on the surface 23. It is desirable for this fuel pressure to be so great that atomisation of the fuel to be injected through the nozzle opening I6 is ensured.

In Fig. 3 the nozzle chamber 24 has a tapered form, the narrow end of the taper being directed towards the nozzle opening I6, so thatthe crosssection of the nozzle chamber 24 diminishes towards the opening I6. Fuel is supplied through spiral grooves 25 at the base of the tapered chamber 24. The outlet 26 for the returning fuel is placed on the outer circumference of the nozzle chamber 24 towards the narrow end. In this Way the circumference of the slot 26 becomes smaller, and as a result the Width of the slot may be greater for a given cross-section and the rein such a Way that the cap 3| is screwed tight,

to the intermediate piece 32. The grooves 33" between the two pieces serve for the supply of 1 fuel and are spirally designed for this purpose. The inner part 34 with the guiding means 35 of the burner needle forms together with the intermediate'part 32 the fuel return flow opening 36` leading from the nozzle chamber 31. Thev inner part 34 is screwed tight to the intermediate pi'ec'e 32 by means of the nut- 33.

All` three parts canY be built together in. the workshop, tested for efficient working. and` accurately adjusted, in order to be screwed as a whole to the burner. pipe 3 before. service. and. to be inserted with this. pipe in the burner 1 The nozzle chamber 31 may have any desired. form.

The inventionoffersthe advantage that atomisation` is not disturbed or influenced. bythe. re.- turning fuel quantity, and further that the manufacture of the burner head andthe guiding and. sealing means. of the nozzle needle are simi plied. Instead. of a. slot-shaped return How opening l0, 26 or 3B, single passages. distributed around the. circumference of the nozzle chamber may also. beprovided, or the slot` may be divided up in. some other manner.

I claim.:

1. A burner for liquid fuel which. comprises. a

supporting. structure. having conduits for supply andreturn. of fuel and. a composite. end portion attached to said structure, said end?. portion consisting of three nested coaxial parts forming a nozzle chamber having. an. inner end toward. said supporting structure, a.l side wall and an. outer end away fromv said supporting structure, the outermost of. said three parts hav'- ing. a nozzle opening centered. on. the. common axis and leading through the. outer end of said chamber to thev outside, the intermediate of.` said three parts having a. relatively large opening centered on the common axis and forming the side. wallof said chamber, the innermost of said three parts forming the inner end of'said chamben, said outermost, intermediate andz innermost parts being. spaced apart to form two' annular fuel passages one on either side of said' inter'- mediate part, one of said. passages leading from the fuel supply conduit and the other to the fuel return conduit, the supply passage being provided with a spiral arrangement for swirling fuel into said chamber.

2. A burner according to claim 1 in which the annular space between the intermediate part and the innermost part of the' end portion forms the supply passage therein.

3. A burner. according to claim. 1 in which the annular spacebetweenl` the intermediate part and the outermost part of the end portion forms the supply passage therein.

4. A burner according to claim 1 in which the nozzle chamber is cylindrical.

5.. A. burner accordi-ng to claim 1 in which the nozzle. chamber isfconical.

6. A burnery according to claim l in which a pipe is connected. to the conduit for return of fuel and a regulating valve is provided for adjusting the quantity of fuel flowing through said pipe? thereby adjusting the amount of fuel discharged from the nozzle opening.

7. A burner according to claim. 1 inwhich the intermediate and in-nermost parts of the. endV portion are carried by a coaxial conduit within. the supporting structure` and in. which. expansion and contraction means inoperative. engagement. with said` structure. and. said. conduit are provided. to maintain a. proper. relative position between the three coaxial parts. during heating and cooling of. the burner..

8. A bur-ner according. to claimI 1 in which the innermost part is provided with a coaxial. open.- ing therethrough and. avalve member is arranged. slidabie in. said opening. forming in its retractedv positionan integral portion of the inner end` of. the nozzle. chamber. and in its extended position. sealing the. nozzle openingV in the outer end. 'ofthe nozzle chamber..

WALTER REFERENCES' CITED The: following; references are: of record in the iileA of this` patent:

UNITED STATES' PATENTS 

